1. Field of the Invention
The present invention relates to a method of normality decision with regard to an ink cartridge, which is detachably attached to a printing apparatus like an ink jet printer or an ink jet plotter, as well as to a printer that actualizes the method.
2. Description of the Related Art
The type of ink usable for a printer generally depends upon the type of the printer, such as the ink jet printer or the dot impact printer. Byway of example, it is assumed that a certain type of ink is usable for a specific printer. If another type of ink, which has different properties from those of the certain type of ink and is not generally used for the specific printer, is mistakenly attached to the specific printer, a desired printing result may not be obtained. In another example, the ink jet printer may encounter the troubles due to a difference in viscosity of ink, such as a poor printing result or clogging nozzles on a print head.
A proposed technique to solve this problem utilizes a first storage unit incorporated in an ink cartridge, in which identification data representing a type of the ink cartridge is stored, and a second storage unit incorporated in a printer main body, in which comparative data for the purpose of comparison are stored. The technique compares the identification data with the comparative data and determines whether both the data are coincident with each other. The printing process continues in the case where both the data are coincident with each other. When both the data are not coincident, on the contrary, the inconsistency is informed and the printing process is discontinued.
The identification data stored in the first storage unit of the ink cartridge may, however, be destroyed by the static electricity or another cause. An oxide layer formed at a contact between the storage unit in the printer main body and the ink cartridge or at a contact between the storage unit in the ink cartridge and the printer main body may cause a failure of electrical contact. In such cases, there is a fear of determining that the ink cartridge is abnormal or unsuitable, while the ink cartridge itself is actually normal and suitable.